172040-91-4Relevant academic research and scientific papers
SAR studies of diphenyl cationic trypanocides: Superior activity of phosphonium over ammonium salts
Dardonville, Christophe,Alkhaldi, Abdulsalam A. M.,De Koning, Harry P.
, p. 151 - 155 (2015)
In previous studies, we have shown that phosphonium salt diphenyl derivatives are attractive antitrypanosomal hit compounds with EC50 values against Trypanosoma brucei in the nanomolar range. To evaluate the role of the cationic center on the t
Photoinduced Inter- and Intra-Ion-Pair Electron Transfer Reactions in N-(p-Benzoylbenzyl)-N,N,N-tri-n-butylammonium Triphenyl-n-butylborate and -Gallate Salts
Hassoon, S.,Sarker, A.,Polykarpov, A. Y.,Rodgers, N. A. J.,Neckers, D. C.
, p. 12386 - 12393 (1996)
The protoreduction of N-(p-benzoylbenzyl)-N,N,N-tri-n-butylammonium triphenyl-n-butylborate (1) and gallate (2) was studied using nano- and picosecond laser flash photolysis.An electron transfer reaction from the borate or the galate counteranion to the excited triplet state of the benzophenone moiety (BP*3) was demonstrated.This reaction leads to the formation of benzophenone radical anion (6) and the boranyl radical, the latter of which dissociates rapidly to form butyl radical.The electron transfer rate was found to depend on the polarity of the solvent.In neat benzene, the short lifetime of the triplet obtained (300 +/- 150 ps) indicates an intramolecular process and that the compounds exist as tight ion pairs.The addition of 1percent MeCN increases the triplet lifetime up to 1.2 ns.The formation of a solvent-separated ion pair was suggested in this solvent mixture.However, in the polar solvent MaCN, 1 and 2 exist partially as free ions as determined by their dissociation constants.A diffusion-controlled intermolecular electron transfer process was shown in this solvent.The p-benzyloxybenzyl radical (BPCH2.), most likely formed by the C-N cleavage bond in the radical anion (6), was identified as an intermediate in the reaction pathway.After the initial electron transfer reaction, this produced tributylamine.The quantum yield obtained for the reaction of 1, 1E-2 M in MeCN, is 0.5 +/- 0.05.Triplet quenching as well as coupling of the radical anion (6) with the butyl radical deriving from decomposition of the borate was suggested to complete with the C-N cleavage reaction.
Tetraorganylborate salts as convenient precursors for photogeneration of tertiary amines
Sarker, Ananda M.,Lungu, Adrian,Mejiritski, Alexander,Kaneko, Yuji,Neckers, Douglas C.
, p. 2315 - 2331 (2007/10/03)
Photoreactions of p-(benzoyl)benzyl trisubstituted ammonium tetraorganylborate salts for the generation of tertiary amines in solution and rigid matrices are described. Structural modification of the complexes allows study of the influence of steric and electronic effects on the photogeneration of amines. Flash photolysis, cyclic voltammetry and product analysis indicate that single electron transfer from borate to excited benzophenone is followed by homolytic C-N bond cleavage. Photoliberation of the tertiary amine is controlled by the rate of the electron transfer reaction.
Photoinduced electron-transfer reactions: Highly efficient cleavage of C-N bonds and photogeneration of tertiary amines
Sarker, Ananda M.,Kaneko, Yuji,Nikolaitchik, Alexander V.,Neckers
, p. 5375 - 5382 (2007/10/03)
The photocleavage of tertiary amine from tetraphenylborates complexed, via ammonium ions, to various chromophore electron acceptors has been studied by laser-flash photolysis. Electron transfer from the borate anions to acceptor excited states is determined to be the primary photochemical step leading to homolytic C-N bond scission and concomitant formation of the corresponding tertiary amine. This pathway was established by direct observation of p-benzoylbenzyl (7a), p-acetylbenzyl (7b), β-naphthylmethyl (7c), and 7-methoxycoumarin-4-methyl (7d) after laser-flash photolysis from N-(4-benzoyl)benzyl-N,N,N-tributylammonium tetraphenylborate (1a), N-(4-acetyl)benzyl-N,N,N-trimethylammonium tetraphenylborate (1b) N,N,N-tributyl-N-(2-methylnaphthalene)ammonium tetraphenylborate (1c), and N,N,N-tributyl-N-(4-methyl-7-methoxycoumarin)ammonium tetraphenylborate (1d), respectively. The presence of radicals (7a-7d) was also suggested by the reaction products. Comparison of the rate constants for quenching of the triplet states from excited (1a, 1b) and singlet states from (1c, 1d) reveals the efficiency of C-N bond cleavage. Quenching constants in the range of 109-1012 M-1 s-1 were observed. Differences are accounted for in terms of variations in the electron-accepting excited states and structural characteristics of the chromophore acceptors.
